Interleaved Triangular Current Mode Totem-Pole PFC Light Load Frequency Limiting Strategy

This paper proposes a light-load frequency limiting method for interleaved triangular current mode (TCM)-controlled bridgeless totem-pole power factor correction (PFC). With the development of third-generation wide bandgap semiconductors, bridgeless totem-pole PFC converters have been widely used in the field of front-end PFC converters due to their advantages of fewer components and a wide zero-voltage switching (ZVS) range. The TCM control method has been used in converters to achieve full-range ZVS. However, when the PFC converter operates under light load, the switching frequency is extremely high, resulting in significant switching losses. Additionally, the TCM control method results in larger current ripple, increasing the current stress on power devices and the core size. By deriving the current control formula under the set maximum frequency limit and introducing interleaved parallel control, the issues of high switching frequency under light load and large current ripple under TCM control are resolved. Measurement results are provided to validate the concept and design process.